| Home | Privacy | Contact |

Airplane Flying Handbook
Transition to Jet Powered Airplanes
STALLS

| First | Previous | Next | Last |

Airplane Flying Handbook

Preface

Table of Contents

Chapter 1,Introduction to Flight Training
Chapter 2,Ground Operations
Chapter 3,Basic Flight Maneuvers
Chapter 4, Slow Flight, Stalls, and Spins
Chapter 5, Takeoff and Departure Climbs
Chapter 6, Ground Reference Maneuvers
Chapter 7, Airport Traffic Patterns
Chapter 8, Approaches and Landings
Chapter 9, Performance Maneuvers
Chapter 10, Night Operations
Chapter 11,Transition to Complex Airplanes
Chapter 12, Transition to Multiengine Airplanes
Chapter 13,Transition to Tailwheel Airplanes
Chapter 14, Transition to Turbo-propeller Powered Airplanes
Chapter 15,Transition to Jet Powered Airplanes
Chapter 16,Emergency Procedures

Glossary

Index

Stall progression sweptwing airplane.
Figure 15-15. Stall progression sweptwing airplane.

The pitch up tendency after the stall is a characteristic
of a swept and/or tapered wings. With these types of
wings, there is a tendency for the wing to develop a
strong spanwise airflow towards the wingtip when the
wing is at high angles of attack. This leads to a
tendency for separation of airflow, and the subsequent
stall, to occur at the wingtips first. [Figure 15-16] The
tip first stall, results in a shift of the center of lift of the
wing in a forward direction relative to the center of
gravity of the airplane, causing the nose to pitch up.
Another disadvantage of a tip first stall is that it can
involve the ailerons and erode roll control.

As previously stated, when flying at a speed in the area
of VMD, an increase in angle of attack causes drag to
increase faster than lift and the airplane begins to sink.
It is essential to understand that this increasing sinking
tendency, at a constant pitch attitude, results in a rapid
increase in angle of attack as the flightpath becomes
deflected downwards. [Figure 15-17] Furthermore,
once the stall has developed and a large amount of lift
has been lost, the airplane will begin to sink rapidly
and this will be accompanied by a corresponding rapid
increase in angle of attack. This is the beginning of
what is termed a deep stall.

As an airplane enters a deep stall, increasing drag
reduces forward speed to well below normal stall
speed. The sink rate may increase to many thousands
of feet per minute. The airplane eventually stabilizes
in a vertical descent. The angle of attack may approach
90° and the indicated airspeed may be reduced to zero.
At a 90° angle of attack, none of the airplane's control
surfaces are effective. It must be emphasized that this
situation can occur without an excessively nose-high
pitch attitude. On some airplanes, it can occur at an
apparently normal pitch attitude, and it is this quality
that can mislead the pilot because it appears similar to
the beginning of a normal stall recovery.

Sweptwing stall characteristics.
Figure 15-16. Sweptwing stall characteristics.

 

15-12